基于切换次序参数化的时滞切换正系统最优控制

考虑时滞线性自治切换正系统,将切换次序参数化作为系统的离散输入,通过系统的等价转换,分析时滞线性自治切换正系统的最优控制问题.利用极小值原理,给出满足性能指标的最优切换次序条件,分析时滞项对性能指标和切换时刻的影响,最后给出数值例子验证结论的有效性.     

一种新的步态特征提取方法的研究

提出一种新的步态特征提取方法,首先利用坎尼算子提取前端腿部的边缘线,并对底部可能产生的误差点进行剔除;接着计算每两帧之间腿部边缘线每个像素点前进的位移,作为原始步态特征;然后,对步态特征进行远近归一化处理,消除被拍摄对象与拍摄镜头之间因距离不同所产生的影响;最后运用主成分分析,将特征空间维度由60维降到3～4维。在识别阶段,用归一化欧式距离计算样本之间的相似程度。提出的这种新的步态特征提取算法在3个人每人4个序列的小样本纯数据库上用最近标本分类器验证所提算法的性能,正确分类率为83.33%;在5个人每人4个序列的小样本混合数据库上,正确分类率为55%。     

浅谈《编译原理》实验课程的改革与实践

《编译原理》作为计算机科学与技术专业的一门重要专业课,其理论性强、系统复杂、难以理解,造成教学效果的不理想。而配套的课程实验是促进学生理解,提高教学质量的有效手段。因此,针对《编译原理》课程的特点,对我院《编译原理》实验课程进行改革并予以实践,效果较好。     

Temperature sensor signal reconstruction for failure detection of vapor compression system

Large effort has been made to fill up databases of failures and diagnosis for all types of technologies and they will remain open lists as systems are dynamically improving. This paper’s purpose is to provide support in decision making, quantification and diagnosis of failures in temperature sensor signal for a vapor compression system. The main challenge regarding this topic has been to distinguish and adapt methods to suit vapor compression systems. The temperature sensor signal failure was experimentally induced to a vapor compression system set-up, failure consequences were analyzed and three detection methods were evaluated: Principle Component Analysis, Fuzzy- Principle Component Analysis and Complex Fuzzy- Principle Component Analysis. All these methods are sensor reconstruction models, trained by the non-failure measured data to build the expected signal. Since faultless measured data are not always available, the possibility to use polynomial extrapolated data (as provided by manufacturer datasheets) is evaluated. The three selected methods showed to be suitable for similar heating, ventilation and air conditioning systems.     

Defending the beauty of the Invariance Principle

Customary stability analysis methods for nonlinear nonautonomous systems seem to require a strict condition of uniform continuity. Although extensions of LaSalle’s Invariance Principle to nonautonomous systems that mitigate this condition have been available for a long time, they have remained surprisingly unknown or open to misinterpretations. The large scope of the Principle might have misled the prospective users and its application to Control problems has been received with amazing yet clear uneasiness. Counterexamples have been used in order to claim that the Invariance Principle cannot be applied to nonlinear nonautonomous systems. Because the original formulation of the Invariance Principle still imposes conditions that are not necessarily needed, this paper presents a new Invariance Principle that further mitigates previous conditions and thus further expands the scope of stability analysis. A brief comparative review of various alternatives to stability analysis of nonautonomous nonlinear systems and their implications is also presented in order to illustrate that thorough analysis of same examples may actually confirm the efficiency of the Invariance Principle approach when dealing with stability of nonautonomous nonlinear systems problems that may look difficult or even unsolvable otherwise.     

Dynamics assignment with MiniMax Principle in decentralized servomechanism

In this paper, we consider a dynamics assignment problem in decentralized servomechanism. The dynamics assignment problem is defined as the problem to assign the dynamics in the reference input. With this assignment, the dynamics of each local controller based on the assignment results are simpler than that based on the original reference input. In this dynamics assignment problem, a criterion based on the total energy of the local controllers among the subsystems is defined and analysed. MiniMax Principle is applied in the paper to do the assignment according to the criteria. The calculations for each assignment result with MiniMax Principle are compared to those by exhaustive search in an example. Monte Carlo experiments are also conducted in the end to illustrate the comparative effectiveness of MiniMax Principle in this dynamics assignment problem.     

Optimal adaptive control of (bio)chemical reactors: past, present and future

In this paper an overview of optimal adaptive control of (bio)chemical reactors is presented. Following the paradigm of the Minimum Principle of Pontryagin the derivation of optimal control sequences for fed-batch production processes is briefly revisited. Next, it is illustrated how the obtained optimal profiles can be exploited in the characterization of nearly optimal control sequences in terms of the qualitative behavior of the specific growth and production rates as function of the limiting substrates. Implementing this knowledge leads in a natural way to the design of (nearly) optimal adaptive feedback controllers. Special emphasis will lie on the potential of on-line biomass measurements (obtained with the Biomass Monitor) in the estimation algorithm of the growth kinetics being the adaptive component of the controller. Extensions towards fermentation processes with (i) multiple substrates and (ii) non-monotonic kinetics are also included. Finally, perspectives towards optimal adaptive control of not perfectly mixed (bio)chemical reactor systems, such as chemical tubular reactors, are outlined.     

医学影像专业“微机原理及应用”教学改革

本文论述我院根据医学影像专业学生计算机知识结构的特点和微机原理及应用课程特点,利用问卷调查反思了教学中存在的问题,并在教学内容、教学方法、实验教学和成绩考核方式等方面进行了改革尝试,合理取舍教学内容,科学利用现代教育技术,将基于问题(Problem-Based Learning,PBL)的教学模式引入实验教学。实践表明,教学改革取得了较好的教学效果。     

属性约简算法CARRDG的改进及其实现技术研究

属性约简算法CARRDG是近来提出的能计算大型信息系统中所有属性约简的高效算法。针对属性约简算法CARRDG在实现技术层面上的可改进之处,在原有的三种约简分辨图深度优先搜索原则（成员独占原则、友人劝阻原则、陌生人吸纳原则）的基础上,增加新的深度优先搜索原则——阻挡层阻挡原则。由于采用了恰当的数据结构和实现技术,使得增加阻挡层阻挡原则不会增加原算法的程序实现的复杂性,也几乎不会增加程序的运行时间。相反,UCI数据实验结果表明,阻挡层阻挡原则对于某些大型信息系统的约简分辨图的剪枝效率超过了成员独占原则与友人劝阻原则。     

化工原理实验多媒体仿真系统程序设计

以可视化Visual Basic 6．0为程序设计语言，用Flash进行动画制作，以Access、Photshop等为辅助工具，在Windows为操作平台下进行多媒体合成开发，设计出化工原理实验仿真系统。该系统涵盖了化工原理实验教学大纲所要求开设的实验内容，具有实验装置认识、实验操作演示、习题测试、仿真实验操作和实验成绩评定等功能；该软件的特点：实验装置的真实感强，实验操作过程生动逼真，软件操作直观、简便、功能强大，系统采用开放式结构，可对内容补充和升级。运用该软件辅助于实验教学中，对于提高学生的综合素质能力及工程实践能力起到了积极的促进作用。本文介绍了该系统的结构与功能、主要程序设计和特点。     

Initial condition of costate in linear optimal control using convex analysis

The Pontryagin Maximum Principle is one of the most important results in optimal control, and provides necessary conditions for optimality in the form of a mixed initial/terminal boundary condition on a pair of differential equations for the system state and its conjugate costate. Unfortunately, this mixed boundary value problem is usually difficult to solve, since the Pontryagin Maximum Principle does not give any information on the initial value of the costate. In this paper, we explore an optimal control problem with linear and convex structure and derive the associated dual optimization problem using convex duality, which is often much easier to solve than the original optimal control problem. We present that the solution to the dual optimization problem supplements the necessary conditions of the Pontryagin Maximum Principle, and elaborate the procedure of constructing the optimal control and its corresponding state trajectory in terms of the solution to the dual problem.     

Gradient geodesic and Newton geodesic HMP algorithms for the optimization of hybrid systems

This paper provides algorithms for the optimization of autonomous hybrid systems based on the geometrical properties of switching manifolds. By employing the notion of geodesic curves on switching manifolds, the Hybrid Maximum Principle (HMP) algorithm introduced in Shaikh and Caines (2007) is extended to the so-called gradient geodesic and Newton geodesic algorithms. The convergence analysis for the algorithms is based upon the Lasalle Invariance Principle and simulation results illustrate their efficacy.     

计算机组成原理教学改革的困境及其出路

计算机组成原理是计算机科学与技术专业不可缺少的一门基础性课程。但是由于该课程具有较强的理论性、实践性和技术性等特点,使其面临着"学生难学,教师难教"的困境。为体现"学生主体地位"和"参与式教学"等教育理念,本文从"学习迁移理论"出发,分析该课程教学改革存在的问题,提出应对现有困境的可能路径。     

高校计算机组成原理课程思政探析及教学改革

以计算机类专业课程计算机组成原理为例,提出计算机组成原理课程思政教学思路,挖掘其中隐藏的课程思政 元素,探析其中蕴含的课程思政理念;同时从教学内容、教学模式、教学方法和手段、教学案例设计几方面介绍计算机组成原理 课程思政教学改革过程。旨在为着力抓好高校课程思政建设,提高学生的政治觉悟、政治素养,树立学生正确的道德观念,真 正做到以文化人、以德育人做出一定的贡献。     

语义词典归类不当现象自动发现

平行周遍原则是陈保亚(1999)提出的一种用于区分词与短语的理论,将词语分为既平行又周遍、平行不周遍和不平行不周遍三类,既平行又周遍的是短语,不宜收入词典。由于汉语语义词典在收词时并未严格遵循平行周遍原则,因此依据现有语义词典可以自动地归纳出许多平行周遍规则或者平行不周遍规则。假定有两部语义词典,则可以归纳出两套平行(不)周遍规则,每一套规则都有各自的正例和反例。一个词典中某一规则的反例如果同时是另一词典中的正例,就意味着前一部词典中的词语可能归类不当。基于这一思路,该文提出一个基于平行周遍原则的语义词典归类不当现象自动发现方法,实验结果证明了这一方法的有效性。     

An impulse control approach to dike height optimization

This paper determines the optimal timing of dike heightenings as well as the corresponding optimal dike heightenings to protect against floods. To derive the optimal policy, we design an algorithm based on the Impulse Control Maximum Principle. In this way, this paper presents one of the first real-life applications of the Impulse Control Maximum Principle developed by Blaquière. We show that the proposed impulse control (IC) approach performs better than dynamic programming with respect to computational time. This is caused by the fact that IC does not need discretization in time.     

Error analysis with the maximum principle

Worst case error analysis using Pontryagin's Maximum Principle is considered for a dynamical system described by a set of differential equations with a separable forcing function. The forcing function is assumed unknown except for bounds on its magnitude. The problem is to determine the maximum value of a given performance criterion. For a wide class of systems the worst forcing term is shown to be "bang-bang." An iterative machine computational algorithm based on the Maximum Principle equations is suggested and analyzed.     

KPCA-模糊加权LSSVM预测方法及其应用

针对工业系统参数缓慢变化和工业现场数据存在噪声和变量间存在多重相关性,提出了一种KPCA-模糊加权LSSVM预测方法;采用KPCA去除数据的噪声和降低样本数据各参数间的多重相关性,减少样本数据维数;针对不同时期样本数据重要程度不一样,提出了模糊加权的思想;利用改进微粒群算法(PSO)优化LSSVM模型的惩罚因子和核函数参数;以净化除钴过程生产数据进行验证分析,仿真结果表明,KPCA一模糊加权LSSVM预测模型精度高于主成分回归(PCR)和LSSVM,能满足工业现场钴离子浓度预测的要求.     

“编译原理与设计”课程三维一体化教学改革

根据编译原理课程的特点,结合"厚基础、宽口径、强能力、高素质"的人才培养目标,研究知识、能力、素质三维一体的编译原理课程改革,提出立足夯实基础,拓宽课程相关领域,训练工程素质,培养学生对系统软件和中、大型软件的规划、组织、设计和实现的综合能力。     

Optimization of pulse frequency modulated control systems via modified maximum principle

The problem of finding the optimum control function for the pulse frequency modulated (PFM) system is considered in this paper. In the PFM systems discussed here, the control function consists of a series of standard pulses. The optimization procedure consists of determining the polarity and positions of the pulses which make up the control function. The performance index is assumed to be a linear combination of the final values of the state variables. This does not exclude the problem of optimizing a system with respect to an integral, provided that the integrand is linear with respect to the state variables, but not necessarily with respect to the control function. In the PFM systems considered, the control function is fixed for a period of time following the initiation of each pulse. This fact precludes the direct application of the existing standard optimizing techniques. The Modified Maximum Principle is presented. It is based on Pontryagin's Maximum Principle and is applicable to open-loop systems with linear plants with fixed operating time. The Modified Maximum Principle is valid for systems with and without final value constraints on the state variables.